From: Jim Hendler <hendler@cs.umd.edu>
Subject: Re: DOCUMENT: Layering document review (was Re: UPDATE: status of longer version of layering document)
Date: Wed, 13 Feb 2002 09:39:03 -0500
> Frank - the problem is that 1-4 as you define them below are
> APPROACHES, not yet proposed solutions to move on. I mean we need to
> figure out how we operationalize these approaches and move to
> language features that support them.
Well, I believe that there already are proposed solutions using approaches
2, 3, and 4.
Approach Proposal
2.Syntax and semantic extension
OWL - http://lists.w3.org/Archives/Public/www-webont-wg/2002Jan/att-0061/01-swol.text
3.Same-syntax, but diverging semantics
DAML+OIL - http://www.w3.org/TR/daml+oil-reference
4.Differing syntax and semantics
OWL' - http://lists.w3.org/Archives/Public/www-webont-wg/2002Jan/att-0061/02-swol.text
What more do you want before having a discussion of which approach to work
with?
You may note that each of these approaches have (roughly) the same language
features. In general, the characteristics of the language do *not* depend
on which approach is taken. (Of course, the syntax details of the language
and the formal specification of the language *do* depend on which approach
is taken, but both of these can be largely ignored when discussing which
approach to take.)
> It is fine and good for the group to decide "We will have a XXX
> syntax and YYY semantic extension" (or whatever), but that doesn't
> say which things will be the same or different from current DAML+OIL
> or why. We clearly need to set philosophy as part of moving ahead,
> but the "task force" I suggested yesterday will need to go through
> D+O figuring out how we change it, if at all, to deal with the issues
> we've been discussing -- I'm trying to be hard-nosed here and remind
> everyone that we need to eventually get this all the way to language
> features.
>
> To date, I see nothing that specific on the table, and we need such.
Well, if the two documents I put together were not specific, then I don't
know what you want.
> For example - a differing syntax solution could be anything from
> "chuck the entire DAML+OIL and start again from scratch using C++
> syntax" to "if we simply add the tag <OWL></OWL> around the OWL
> equivalent of daml:class statements then everything works again" --
> that's quite a range! Also, it is complicated by the fact that some
> of our reasoning may need to go like this:
> If RDF were changed to allow XXX then our language works as is (or
> with the following minor modification)
> if not, then we need to drastically change our language to YYY (for
> example, largely abandoning RDF syntax)
>
> which is the best way we could be able to communicate this sort of
> thing back to an RDF WG (either Core or future RDF 2.0) for
> consideration or joint solution.
It would, I suppose, be possible to state some changes to RDF(S) under
which each of the approaches could be considered to be an extension of
RDF(S).
[...]
> -JH
Peter F. Patel-Schneider
Bell Labs Research